Dame na Kurai ga Choudoii

From Attractive Fascinante:

1) Two History Teachers

2-2.5) The Crisis of Yamabuki-kun, The Power of Youth
Yamabuki is an average guy with an ordinary face, average grades, and a normal life and he likes it that way. Then he meets Aonuma...

3-6) The Good-for-Nothing Fellow is Just Good
Odagiri Itaru, an elementary sensei, went to his student, Aoyagi Rikuto’s house for a house visit to find out the reason that Rikuto was always sleeping in class. To his surprise, Rikuto was always helping his mangaka father, Aoyagi Kaiji, on his works. Odagiri always came over to their house to make sure that Rikuto slept on time. As time went by, Odagiri started to have feelings for Kaiji. But would he be able to become that irreplaceable existence in Kaiji’s heart?